Dynamo-electric machine.



C. H. BEDELL. 'nYNAMo ELECTRIC MACHINE. APYLIGATION FILED OUT. 27, 1906.

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0. H. BEDELL. DYNAMQ ELECTRIC MA HI E. I nrncnlox Hum 001. 90s. I 1,010,216 Patented Nov. 28, 19-1 1.

$HEET2 2BKEET P WITNESSES:

INVENTOR.

ATTORNEYS.

UNITED STATES PATENT OFFICE...

CHARLES H. BEDELL, 0F BAYONNE, NEW JERSEY, ASSIGNOR TO ELECTRG--DYI[ I'AMIC COMPANY, OF BAYONNE, NEW! JERSEY, A CORPORATION 033 NEW JERSEY.

DYNAMIC-ELECTRIC MACHINE.

Specification of'Iietters Patent. Patemtigd N 28 19? Application filed October 27, 1906.

Serial No. 340,853.

To all whom it may concern:

Be it known that 1, CHARLES H. BEDELL, a citizen of the United States, residing at Bayonne, county of Hudson, in the State of New Jersey, have invented certain new and useful Improvements in Dynamo-Electric Machinesg-and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable o hers skilled in the art to which it appertains to make and use the same.

Fifty invention relates particularly to that class of multipolar dynamo electric 1nachines, in which sparkless commutation is attained by creating a commutating field adaptedto generate in the armature coils undergoing commutation, an electro-motivc force in the proper direction and of proper amount to secure sparkless commutation. It has heretofore been proposed to secure this result in multi-polar dynamo electric machines in various Ways, as for example, by providing auxiliary poles between the main poles for the purpose of creating the desired commutating field, or by winding the appropriate tip ot the main pole wlth an auxiliary commu- -tating coil, and in other similar ways known to the art. In such machines, however, it has been customary to create the desired commutating field by means of electro magnets wound with existing coils connected in series with the armature and carrying the whole armature current. In such case, the field of the comniutating poles may bear an approximately constant relation to the opposing pole in the armature, if each arma turc circuit is carrying at all times substantially the same current as every other armature circuit, which-would be the case it the ari'nature were wound with a wave wii'iding, so that each armature circuit; has substantially the same fraction of its length under each pole of the machine. In machines ha ving parallel or lap winding, however, this condition does not exist, and one armature circuit may have all, or substantially all. of its length under one pole, or under two adjacent poles in the machine, every other armature circuit having all, or substant ally all, of its length undo another one, or two other adjacent poles in the machinez- In such case, it the strength of the magnet field under one pole is different from the strength of the magnet field under another pole for any reason, or if the armature is not accurately centered in its bearings, or it for any other reason the air gap under one pole of the machine is different from the air gap under another pole of the machine, then there result in the different armature circuits currents of different strength. it new in such machines the auxiliary commutating field is, as has heretofore been customary, created by an electro-magnet energized by coils in series with the armature as a whole, the strength of the commutating fields do not partake of the differences in the strengths oi the armature currents in the dillferent armature circuits, but, on tie contrary, remaih at all times equal, irrespective of the ditl'ercnces in the strengths of the currents in the different armature circuits. The result of this is that the different commutating fields are not always of the proper strength to secure. sparkless commutation, and sparking results. I

The object of my invention is to overcome this difficulty in machines in which such unbalanced condition of the currents in the different armature circuitsis liable to exist, and l accomplish this result by making an unbalancing of the current st ength in. the di'tl'eren't armature circuits etlectire on the strength of the commutating fields.

In order to make clear to those skilled in the art the nature and mode of operation of my invention, l have illustrated in the accompanying drawings two cml'iodin'ients of it.

Figure 1 represents diagran'nnatically a. variable speed dircctecurrent dynanm-elec- 'tric--machine having :tour main poles and tour interpoles and liaving an armature with a parallel ringwinding. Fig. 2 reprc Hit-11in a rariablc speed, direct-current dynamo-clectric machine ha ring tour main poles and tour inter-polesand having an armature with a parallel drum winding.

It will he understood, however, that my invention is applicable to any type of dynamo-electric machine either generator or motor and lowing -a'ring, drum or a disk armature, so long a For any reason the currents carried in the dill'crent armature circuits are liable to variation in strength with lGS}')G 't to one another.

l letcrring to Fig. l oi": the drawings, A. B, C and D represent the tour main poles of a shunt wound variable speed dynamo assume that the direction of rotation is such that the current [lows in the armature circuits in the direction indicated by the small arrows. In order to maintain the. commutoting fields at all times of the proper a variable resistance strength to secure sparhless commutation under the circumstances above specified, 1

.wind each inter-pole with a winding. one end of which is connected to that brush which is coinmutating the armature coil or coils directly beneath the particular interpole and the otherend of which is connected to the external circuit. That. is, the winding It on the inter-pole it. connected to the brush E; the winding 0 on the interpole ii is connected to the brush F, the winding 1 on the interpole t." is connected to the brush (it, the winding (3 on the intcrpole D is con nected to the brush ll. The other ends ot' the windings t) and Q, which are connected to the positive brushes l and ii are connected. together to the positive lead '1, and the other ends ot the windings N and l" which are in circuit with the nt' gative brushes 1.) and G are connected to the negative lead :3. Though 1 have shown the winding N on the pole It connected to the brush E, which is directly opposite that pole, it will be under;-,=tood that it' the armature connectors are twisted, as sometimes the case, this brush may not be directly beneath the pole.

in Fig. 2 of the drawings represented a. machine in all rcsgects similar to that shown inhig. 1, excepting that the machine shown in Fig. 2 has a. parallel wound drum armature. The rel'ercncc letters in the two figures correspond excepting that the arntature in Fig. 2 is lettered M;

It will be observed that by this construction l secure a commutating lield which is not only substantially proportional to the .whole armature current, as has heretofore been the case, but 1 secure a connnutating' field at each point of commutation which is e'tl'ected by an unlu'tlancing o't'the current strength in the dill'erent armature circuits.

will he understood that. instead of using the current from each brush to create its conunutating field the current may be used chine a parallel wound armature,

only to regulate the field, and yet retain the characteristic feature of my invention which is that the commutating field shall vary as the current at the brush varies, or in other words that the connnutating field shall be a function of that current.

By the term current e ollector I intend to include any device making contact with the tainunutator through which the current flows into or out of the armature.

What 1 claim is 1. In a multipolar dynamo electric machine, a parallel wound armature, a plurality of positive current collectors and a plurality of negative current collectors, conductor leads extending from the'several current collectors to the distribution mains, a plurality of conuuutati'ng poles, andexciting windings for said poles connected in the several leads, to make an unbalancing ot' the current st'rtaigtl'i in the diti'erent arn'iature circuits etl'ective on the strength of the cominutating fields.

2. A nuilti-polar dynamo-electric machine ha viuga parallel wound armature and a plurality of con'ni'uitating poles, a coil on each commutating pole, and connections between each coil and that current collector which is conu'uutating armature coils directly beneath that particular eoinmutating ole.

2%. .ln a ariable speed niulti-polar dynamo electric machine a parallel wound armature, a plurality of field poles havingexciting windings in shunt t0 the armature, a variable resistance in said shunt, a plurality of commutating fields and means for creating i'ariations in the strength of each connnutating tield corresponding tojthe variations in strength of the current flowing into the current eollector associated with that held, substantially as described.

1-. in a niulti polar dynamo-electric maa plurality of negative current collectors, a plurality of positive current collectors, a conunutating pole associated with each current collector, and an exciting winding on each commutating pole connected between its current collector and the external circuit, substantially as described.

in testimony whereof l atlix my signature, in presence of two witnesses.

tlllilltlqlfib ll. BEDELL.

\Vitnesses Hermon Ronmison, ldicnanr, A. (Filam It is hereby certified that in Letters Patent No. 1,010,216, granted November 28,

1911, upon the application of Charles H. Bedeli, 0t Bayonne, New Jersey, for an improvement in I)yna1noEleetric Machines," an error appears in the printed specification requiring correetion as foliows: Page 1, line 32, for the word existing read waiting; and that the said Letter.- Putent should be read with this correction therein that the same may conform to the record of the chse in the Patent 0111094 Signed and sealed this 16th day of January, A. D., 1912.

[SEALJ C. C. BILLINGS,

Acting Commissioner of Patents. 

